Bottom Line:
Recent studies suggest that cell therapy may be an effective way to repair intervertebral disc degeneration.As a strong immune suppressor, TGF-β1 has been shown to inhibit inflammation respond effectively.However, the NF-κB positive cells were significantly less than other two control groups.

ABSTRACTRecent studies suggest that cell therapy may be an effective way to repair intervertebral disc degeneration. As a strong immune suppressor, TGF-β1 has been shown to inhibit inflammation respond effectively. The objective of this study was to explore the effects of TGF-β1 during bone marrow mesenchymal stem cells-based therapy for disc degeneration. In vitro assays demonstrated that co-culturing of nucleus pulposus cells with bone marrow mesenchymal stem cells resulted in significantly higher levels of TGF-βl secretion. This increase inhibited IκB phosphorylation and NF-κB activation, detected by western blot analysis. Meanwhile, in a rabbit model, MRI analysis revealed significant recovery of signal intensity in the degenerative discs of rabbits receiving cells transplantation, than receiving cells treated with a TGF-β1 inhibitor or saline. These findings indicated that enhanced TGF-β1 production recovered the degeneration of intervertebral disc. And also immunohistochemical staining detected enhanced collagen II expression in the rabbits treated with cell transplantation. However, the NF-κB positive cells were significantly less than other two control groups. Thus, cell therapy promoted TGF-β1 expression in nucleus pulposus, leading to anti-inflammatory effects via the inhibition of NF-κB, and the amelioration of disc degradation due to increased expression of collagen II and aggrecan in degenerative intervertebral disc.

f8: NF-κB immunohistochemical staining (×200).The expression of NF-κB was more apparent in the BMSCs transplantation group (8 weeks). Quantification of immunohistochemical staining showed that the BMSCs transplantation had significantly lower mean optical density than the TGF-β1 specific inhibitor-treated and saline group. And the expression NF-κB also decreased over time significantly. (*p < 0.05, compared to BMSCs transplantation group; #p < 0.05, compared to mean optical density at 4 weeks).

Mentions:
To understand that suppression effects of TGF-βl in NF-κB-dependent inflammation are responsible for the protection against rabbit disc degeneration, we next used immunohistochemistry to detect the expressions of TGF-βl and NF-κB. Immunohistochemical analyses revealed that the expression of TGF-βl increased over time in the BMSCs transplantation group, and also the expression in these discs was significantly higher compared to those detected in the saline and SB431542 groups. (p < 0.05) (Fig. 7). However, the expression of NF-κB decreased over time in BMSCs transplantation group. And the expression was significantly lower compared to two control groups. (p < 0.05). On the other hand, the expressions of both TGF-βl and NF-κB in SB431542 group was no significant differences when compared with the saline group. (p > 0.05) (Fig. 8).

f8: NF-κB immunohistochemical staining (×200).The expression of NF-κB was more apparent in the BMSCs transplantation group (8 weeks). Quantification of immunohistochemical staining showed that the BMSCs transplantation had significantly lower mean optical density than the TGF-β1 specific inhibitor-treated and saline group. And the expression NF-κB also decreased over time significantly. (*p < 0.05, compared to BMSCs transplantation group; #p < 0.05, compared to mean optical density at 4 weeks).

Mentions:
To understand that suppression effects of TGF-βl in NF-κB-dependent inflammation are responsible for the protection against rabbit disc degeneration, we next used immunohistochemistry to detect the expressions of TGF-βl and NF-κB. Immunohistochemical analyses revealed that the expression of TGF-βl increased over time in the BMSCs transplantation group, and also the expression in these discs was significantly higher compared to those detected in the saline and SB431542 groups. (p < 0.05) (Fig. 7). However, the expression of NF-κB decreased over time in BMSCs transplantation group. And the expression was significantly lower compared to two control groups. (p < 0.05). On the other hand, the expressions of both TGF-βl and NF-κB in SB431542 group was no significant differences when compared with the saline group. (p > 0.05) (Fig. 8).

Bottom Line:
Recent studies suggest that cell therapy may be an effective way to repair intervertebral disc degeneration.As a strong immune suppressor, TGF-β1 has been shown to inhibit inflammation respond effectively.However, the NF-κB positive cells were significantly less than other two control groups.

ABSTRACTRecent studies suggest that cell therapy may be an effective way to repair intervertebral disc degeneration. As a strong immune suppressor, TGF-β1 has been shown to inhibit inflammation respond effectively. The objective of this study was to explore the effects of TGF-β1 during bone marrow mesenchymal stem cells-based therapy for disc degeneration. In vitro assays demonstrated that co-culturing of nucleus pulposus cells with bone marrow mesenchymal stem cells resulted in significantly higher levels of TGF-βl secretion. This increase inhibited IκB phosphorylation and NF-κB activation, detected by western blot analysis. Meanwhile, in a rabbit model, MRI analysis revealed significant recovery of signal intensity in the degenerative discs of rabbits receiving cells transplantation, than receiving cells treated with a TGF-β1 inhibitor or saline. These findings indicated that enhanced TGF-β1 production recovered the degeneration of intervertebral disc. And also immunohistochemical staining detected enhanced collagen II expression in the rabbits treated with cell transplantation. However, the NF-κB positive cells were significantly less than other two control groups. Thus, cell therapy promoted TGF-β1 expression in nucleus pulposus, leading to anti-inflammatory effects via the inhibition of NF-κB, and the amelioration of disc degradation due to increased expression of collagen II and aggrecan in degenerative intervertebral disc.